Tub Shower Magic (Dawn White Vinegar) 12 ounces white vinegar 12 ounces liquid, blue Dawn detergent Directions: 1 Heat vinegar in microwave until hot and pour into squirt bottle. 2 Add the Dawn soap. Put the lid on and gently shake to incorporate. 3 You now have a powerful cleaning product that will melt soap scum and tub and shower buildup, clean sinks, appliances and just about anything. Just spray it on, scrub, rinse and be amazed.